Twigacycline contains Oxytetracycline which belongs to the group of tetracyclines and acts bacteriostatic against many Gram-positive and Gram-negative bacteria like Bordetella, Campylobacter, Chlamydia, E. coli, Haemophilus, Mycoplasma, Pasteurella, Rickettsia, Salmonella, Staphylococcus and Streptococcus spp.   The action of oxytetracycline is based on inhibition of bacterial protein synthesis. Oxytetracycline is mainly excreted in urine, for a small part in bile and in lactating animals in milk.